Nadab and Abihu
1 Nadab and Abihu were two of Aaron's sons, but they disobeyed the Lord by burning incense to him on a fire pan, when they were not supposed to. 2 Suddenly the Lord sent fiery flames and burned them to death. 3 Then Moses told Aaron that this was exactly what the Lord had meant when he said:

“I demand respect
from my priests,
and I will be praised
by everyone!”

Aaron was speechless.
4 Moses sent for Mishael and Elzaphan, the two sons of Aaron's uncle Uzziel. Then he told them, “Take these two dead relatives of yours outside the camp far from the entrance to the sacred tent.” 5 So they dragged the dead men away by their clothes.
6 Then Moses told Aaron and his other two sons, Eleazar and Ithamar:
Don't show your sorrow by messing up your hair and tearing your priestly clothes, or the Lord will get angry. He will kill the three of you and punish everyone else. It's all right for your relatives, the people of Israel, to mourn for those he destroyed by fire. 7 But you are the Lord's chosen priests, and you must not leave the sacred tent, or you will die.
Aaron and his two sons obeyed Moses.
8 The Lord said to Aaron:
9 When you or your sons enter the sacred tent, you must never drink beer or wine. If you do, you will die right there! This law will never change. 10 You must learn the difference between what is holy and what isn't holy and between the clean and the unclean. 11 You must also teach the people of Israel everything that I commanded Moses to say to them.
12 Moses told Aaron and his two sons, Eleazar and Ithamar:
The grain sacrifice that was offered to give thanks to the Lord is very holy. So make bread without yeast from the part that wasn't sent up in smoke and eat it beside the altar. 13 The Lord has said that this belongs to you and your sons, and that it must be eaten in a holy place. 14-15 But the choice ribs and the hind leg that were lifted up may be eaten by your entire family, as long as you do so in an acceptable place. These parts are yours from the sacrifices that the people offer to ask the Lord's blessing. This is what the Lord has commanded, and it will never change.
16 When Moses asked around and learned that the ram for the sin sacrifice had already been burned on the altar, he became angry with Eleazar and Ithamar and said, 17 “Why didn't you eat the meat from this sacrifice in an acceptable place? It is very holy, and the Lord has given you this sacrifice to remove Israel's sin and guilt. 18 Whenever an animal's blood isn't brought into the sacred tent, I commanded you to eat its meat in an acceptable place, but you burned it instead.”
19 Their father Aaron replied, “Today two of my sons offered the sacrifice for sin and the sacrifice to please the Lord, and look what has happened to me! Would the Lord have approved if I had eaten the sacrifice for sin?”
20 Moses was satisfied with Aaron's reply.
The Sin of Nadab and Abihu
1 Aaron's sons, Nadab and Abihu, each took his fire pan, put live coals in it, added incense, and presented it to the Lord. But this fire was not holy, because the Lord had not commanded them to present it. 2 Suddenly the Lord sent fire, and it burned them to death there in the presence of the Lord. 3 Then Moses said to Aaron, “This is what the Lord was speaking about when he said, ‘All who serve me must respect my holiness; I will reveal my glory to my people.’” But Aaron remained silent.
4 Moses called Mishael and Elzaphan, the sons of Uzziel, Aaron's uncle, and said to them, “Come here and carry your cousins' bodies away from the sacred Tent and put them outside the camp.” 5 So they came and took hold of the clothing on the corpses and carried them outside the camp, just as Moses had commanded.
6 Then Moses said to Aaron and to his sons Eleazar and Ithamar, “Do not leave your hair uncombed or tear your clothes to show that you are in mourning. If you do, you will die, and the Lord will be angry with the whole community. But all other Israelites are allowed to mourn this death caused by the fire which the Lord sent. 7 Do not leave the entrance of the Tent or you will die, because you have been consecrated by the anointing oil of the Lord.” So they did as Moses said.
Rules for Priests
8 The Lord said to Aaron, 9 “You and your sons are not to enter the Tent of my presence after drinking wine or beer; if you do, you will die. This is a law to be kept by all your descendants. 10 You must distinguish between what belongs to God and what is for general use, between what is ritually clean and what is unclean. 11 You must teach the people of Israel all the laws which I have given to you through Moses.”
12 Moses said to Aaron and his two remaining sons, Eleazar and Ithamar, “Take the grain offering that is left over from the food offered to the Lord, make unleavened bread with it and eat it beside the altar, because this offering is very holy. 13 Eat it in a holy place; it is the part that belongs to you and your sons from the food offered to the Lord. That is what the Lord commanded me. 14 But you and your families may eat the breast and the hind leg that are presented as the special gift and the special contribution to the Lord for the priests. You may eat them in any ritually clean place. These offerings have been given to you and your children as the part that belongs to you from the fellowship offerings of the people of Israel. 15 They shall bring the hind leg and the breast at the time the fat is presented as a food offering to the Lord. These parts belong to you and your children forever, just as the Lord commanded.”
16 Moses asked about the goat for the sin offering and learned that it had already been burned. This made him angry at Eleazar and Ithamar, and he demanded, 17 “Why didn't you eat the sin offering in a sacred place? It is very holy, and the Lord has given it to you in order to take away the sin of the community. 18 Since its blood was not brought into the sacred Tent, you should have eaten the sacrifice there, as I commanded.”
19 Aaron answered, “If I had eaten the sin offering today, would the Lord have approved? The people presented their sin offering to the Lord today, and they brought their burnt offering, but still these terrible things have happened to me.” 20 When Moses heard this, he was satisfied.